Problem: Simplify the following expression: $k = \dfrac{2rp - 5p}{4qp + p} - \dfrac{3rp}{4qp + p}$ You can assume $p,q,r \neq 0$.
Solution: Since the expressions have the same denominator we simply combine the numerators: $k = \dfrac{2rp - 5p - (3rp)}{4qp + p}$ $k = \dfrac{-rp - 5p}{4qp + p}$ The numerator and denominator have a common factor of $p$, so we can simplify $k = \dfrac{-r - 5}{4q + 1}$